Vista Backup Utility : Incremental backup questions

  • Thread starter Nicholas Thompson - Me
  • Start date

Nicholas Thompson - Me

I'm using the Vista backup utility every week. On the first week I did a
full Backup and since then I've been doing incrementals. Oh, I have the
Vista Home Premium version of Backup. I've noticed that my incremental
backups are very large (gigabytes) despite fact that I've hardly made any
changes/additions to my files since the previous backup. Does anyone know
why this might be?


If I remember correctly, Vista file backup (unlike its counterpart, Complete
PC Backup) doesn't make use of VSS technology and thus seems to recopy large
amounts of user files).


Jill Zoeller [MSFT]

True indeed. It's covered in our FAQ at

Here's the text:

My backups are larger than I expected. Doesn’t File Backup use VSS to make
the incremental backups small, like in Complete PC Backup?

Complete PC and File Backup are very different in terms of how they make use
of VSS. File Backup creates a shadow copy (also known as a snapshot) using
VSS to make sure that all opened files are flushed from memory to the file
system. Once this is done, File Backup reads the files from the snapshot and
places them in a zip file. The zip file will contain complete files from
both a full and incremental backups, so this is why the zip file is larger
than you might expect.

File Backup does not make use of snapshots to store incremental block-level
changes to files like Complete PC Backup does. For example, if you had a
Microsoft PowerPoint presentation that was 10 MB, the first time you backed
it up using File Backup, it would take up 10 MB. But if you then added some
slides to it and it grew to 11 MB, your next incremental backup will include
a complete new copy of it. On the other hand, with Complete PC Backup, the
first time it will back up 10 MB, but the second time, it will only capture
the block-level changes (within the file), which could be as little as 1


I noticed this also, with Windows Backup and Acronis. It turned out (as far
as I can tell) that Vista's aggressive indexing utility seems to be actually
making files appear to have been modified when it indexes them, so the
"incremental" backups are actually backing up the same files every time. I
started suspecting something like this was happening when I clicked Recently
Changed and saw HUNDREDS of mp3 files listed there that I haven't (and
COULDN'T) have accessed myself recently.

When I turned indexing off, my incremental backups became drastically
smaller in size. The Recently Changed folder also dropped to just a few

I have contact Acronis about this to see if they can confirm it and,
hopefully, modify their software so I can turn indexing back on in Vista
again. Will also hope Microsoft modifies either the indexing utility or
their backup software to deal with this, unless of course I'm completely
incorrect about this being the cause.

Jill Zoeller [MSFT]

The Indexing team says that indexing should not be causing changes to your
files; the most likely culprit is your antivirus software. However, we'd
like to investigate this further.

Can you give us the exact steps you used to reproduce what you are seeing?


I'm not really following how the Indexing team can claim that. I had
indexing turned off for my music folders. Virus software (AVG) has never
been shut down. When I check the Recently Changed folder, I see 40 or 50
docs and image files, nothing else.

I reset the Indexing options, adding the music folders and tell the system
to rebuild the index. Immediately the Recently Changed folder begins showing
files as they are indexed. If the system thinks something is Recently
Changed, that would seem to include it in the next incremental backup, don't
you think?

Whatever is doing this, it's NOT the virus software and it really looks to
me like it's the indexing system.

Jill Zoeller [MSFT]

Rjw, are you familiar with the Filemon tool? This will allow you to watch
what is changing files and confirm the culprit. You can generate a log file
that we'd be interested in seeing if Indexing Service turns out to be the

This posting is provided "AS IS" with no warranties, and confers no rights.

Want to learn more about Windows file and storage technologies? Visit our
team blog at


Jill: Thanks for the suggestion regarding Filemon, but it appears from the
link you provided it was rolled into Performance Monitor at some point and
Vista's Performance Monitor is a TAD too complicated for me to figure out at

I'm going to just drop this thread for now and hope that eventually someone
figures out why incremental backup sets are as large as the original set so
we can fix it. In the meantime, I'll manually back up my music and avoid
incremental backups.

Thanks for your interest and suggestions and good luck figuring this out.
I've noticed many other folks in the forums asking about exactly the same


Ronnie Vernon MVP

Hi Jill,

Apparently they have combined Filemon, Regmon into the Process Monitor
program for use with Vista. Process Monitor now has 3 buttons.

Show Registry Activity (regmon)
Show file activity (filemon)
Show process and thread activity (process monitor)

You can still download each program separately, but if you install regmon or
filemon on Vista, on first use, you will get a message stating that "this
program is part is now part of process monitor" for Vista?

This would be good information to post on the Filing Cabinet Blog.


Ronnie Vernon
Microsoft MVP
Windows Shell/User

Jill Zoeller [MSFT]

Thanks for letting me know about the new Process Monitor. The developer who
suggested Filemon hadn't mentioned this. I see the "Show File Activity"
button and I hope that makes it easier for rjw to see the file activity.

Jill Zoeller [MSFT]

rjw, as Ronnie mentioned, it's easy to filter out all but the file activity
using the buttons on the toolbar. Give it another try if you have a chance.

Ronnie Vernon MVP


Your welcome. I just stumbled across that information when I went to the
download site to make sure I had the most recent versions.


Ronnie Vernon
Microsoft MVP
Windows Shell/User

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question